An optoelectronic device is a device that exhibits a relationship between the device's optical characteristics and the device's electrical characteristics. For example, some optoelectronic devices accept visible light, infrared light, ultraviolet light, x-rays, or electromagnetic waves in other wavelengths, and produce a potential difference or voltage across a set of terminals. A photodiode is an example of this type of photodetector optoelectronic devices. Some optoelectronic devices similarly accept light or electromagnetic waves in other wavelengths, and switch from conducting to non-conducting or vice-versa, for electrical current configured to pass through the device.
Some other optoelectronic devices accept an electrical current as input and output visible light, infrared light, ultraviolet light, x-rays, or electromagnetic waves in other wavelengths. This type of optoelectronic device is called a light-emitting diode, or a photoemitter. A photodetector or a photoemitter optoelectronic device fabricated at a semiconductor device scale using semiconductor materials and fabrication technology is a semiconductor optoelectronic device.
Surface plasmons (also referred to herein as simply “plasmons”) and excitons are both important optoelectronic phenomena. Surface plasmons are charge oscillations coupled to optical fields. Plasmons can concentrate optical fields into nanoscale volumes and enhance the efficiency of photodetectors. This concentration of optical fields can also serve to enhance the rate of luminescence from nearby optically or electrically driven emitters.
Excitons comprise electrons bound to electron holes in semiconductors. Excitons are an important process in both photoemission and photodetection, particularly in organic molecules and nanomaterials, where the Coulomb binding strength between electrons and holes is especially strong.
Surface plasmons can hybridize with excitons when they are brought close together. When a surface plasmon is sufficiently strongly coupled to an exciton, the resulting quasiparticle is known as a plasmon-exciton polariton (PEP). To achieve a PEP in practice, because metal surfaces are the most common host for surface plasmons, light-absorbing molecules (referred to herein as simply “molecules”), such as dye molecules, are often placed near metal surfaces, or metal antennas. This type of plasmon-exciton polariton is known as a hybrid polariton, because the plasmon and exciton that form the polariton are hosted by separate materials.